Mercury switch



Oct. 137`f193l.

P. K. CRAMBLET MERCURY SWITC H Filed Nov. 24, 1928 MMMMM maw) - may be varied.

Patented Oct. 13, 1931.

'UNITED STATES PATENT OFFICE' PAUL K. CRAMBLET, Olli' MILWAUKEE WISCONSIN, ASSIGNOR, BY MESNE ASSIGNMENTS, TO MINNEAPOLIS-HONEYWELL REGULATOR COMPANY, 0F MINNEAPOLIS, MINNE- SOTA, A v('}OB.IPOBIA.'.I.ION 0F DELAWARE mnncUnY swrrcn Application led November 24, 1928. Serial No. 321,570.

-This invention relates in general to mercury switches and more particularlyv tothe mercury switch of the type having. a protective element of arc resisting material for receiving and withstanding the shock and strains resulting from arcmg and from the high temperature and rapid temperature uctuations incident thereto.

One of the principal objects of the present invention is to rovide a mercury switch of this character w ich is of simple and durable construction, reliable and eil'ective in operation and easy and comparatively inexpensive to manufacture.

In carrying out these purposes, a mercury switch is constructed with an outer envelope of soft glass or other suitable material in which a protective quartz, porcelain, or other arc resisting material is assembled. The outer envelope lhas in its upper portion an'outwardl directed enlargement in which one end of t e protective element is disposed. Yieldablesupporting means such as a ring of cement or the like is interposed between the inner wall of the outwardly-directed enlargement of the outer envelope and the protective element whereby the protective element vis yieldably although directly suspended upon the outer envelope. Obviously, the particular construction employed for eil'ectiig this yieldable suspension directly on the outer envelope The lower end of the protective element provides a well receiving a portion of a body of mercury placed in the outer envelope. The body of mercury also 'hasa shiftable portion in' the outer envelope which makes and breaks contact with the pori tion in the well on a surface ofthe protective element. Electrodes are sealed through the outer envelope and immersed in the mercury in the well jand in the shiftable portion of the mercury respectively. The protective element is fashioned to provide a protecting shield for the electrode projecting down into the mercury in the well to prevent direct contact between the shiftable portion of the mercury and such electrode. This shielding is effected by cutting spaced slots in the protective element and depressing the portion thereelement of hard glass,

of between the slots inwardlyV towards the electrode to be protected. Of course, the protective element must be heated and rendered plastic to permit of this construction in the rst instance. tive element not only provides the shield but also provides the opening through which the portions of the mercury unite and divide and the surface on which the make and break occurs. v

Other objects and advantages reside in certainnovel features of the construction, arrangement and combination of parts which will be hereinafter more fully described' and particularly pointed out in the appended claims, reference being had to the accompanying drawings forming appart of this and in which: in central vertical longlspecification,

Figure 1 1s a view tudinal section showlng a mercury switch embodying the present invention and illustrating the sameas positioned when the portions of the mercury are divided and the circuit controlled by the switch is broken;

Figure 2 is a similar view illustrating the `This structure'of the protec' switch as positioned when the portions of the mercury are united;

Figure 3 is a view in transverse lvertical section taken on line 3-3 of Figure 2; and Figure 4 is a view in horizontal section taken on line 4--4 of Figure 2.

Referring to the drawings, thenumeral 1` designates anouter envelope which may be constituted of soft glass or any other suitable material. Within the outer envelope 1 a protective element 2 of arc resistingumaterial is provided and may be constituted of hard glass, quartz, porcelain, aluminum oxide, or any other suitable arc-resisting material. The outerf envelope 1 has a main body portion 3 and an outwardly: directed cylindrical enlargement 4, the enlargement 4 of the envelope projecting outwardly from the upper portion-thereof.

As shown in 'Figures 1 to 3, the protective element 2 has the general form of a cylinder closed at its lower end and open at its upper end, The'upper open end 4 of the cylinder 4 which constitutes the attaching portion thereof, is supported within the en argement by means of a ring of cement or the like, or by virtue of the pro-vision of other yieldable supporting means between the upper end of the protective element 2 and the inner wall ofthe enlargement 4. rlhe cement 5 is suliiciently rigid and solid to firmly hold the proc tective element 2 in proper position but is Y arcing zone,

suliciently yieldable to prevent the transmission of shocks and strains between the protective element and the outer envelope. 0f course, when set, the cement adheres tenaciously to both the protective element and the outer envelope.

A body of mercury designated generally at 6 is provided within the switch and has a portion 6a filling the well provided by the lower closed end of the protective element and a shiftable portion 6h which alternately unites with and divides from the portion 6L in the well. An electrode 7 is sealed in through the upper end of the outwardly displaced enlargement or supporting portion 4 of the outer envelope and projects down into the portion 6a of the mercury. An electrode 8 is sealed in through one end of the outer envelope and is constantly immersed in the shiftable portion 6b of the mercury.

To provide the opening through which the portions of the mercury may unite and divide and to shield the electrodes 7 against direct contact with the shiftable portion 6b of the mercury, the protective element is provided with a shield 9 for the electrode 7 and with an opening 10 through which the shiftable portion 6b of the mercury may pass. Preferably the shield 9 and opening 10 are formed prior to the assembly of the protectivev element with the switch and are produced by providing spaced slots in the protective element and pressing the portion of the rotective element between the slots inwar ly after such portion has been heated to render it suiiiciently plastic to permit of this operation. Of course, when the protective element cools down it will have the structure shown in the drawings. lllhe floor or lower wall of the -lower slot which provides the opening 10 also affords an arc receiving surface 10 which may be glazed to be better adapted to stand up under the arc.

With this construction, the protective element 2 has a direct though yieldable suspens1on upon the upper portion of the outer envelope and the lower portion and main body of the protective element is spaced from and out of ContactJ with the outer envelope as shown in the drawings. The organization ha s the further advantage of positioning the supporting portion of the outer envelope at a point relatively remote withl respect to the and it lends itself readily to a switch in which the circuit is made and Jbroken by a mercury to mercury make and break, and wherein all danger of direct con tact between the shiftable portion of the merreeaeee cury and the electrode connected to the other` side of the circuit is precluded. llt is to be understood that the outer end of the enlargement 4 of the outer envelope is open when the protective element is ,assembled with the outer envelope. After the protective element has been assembled and the supporting ring 5 has been built up or otherwiseo'peratively associated with the protective: element and the outer envelope, then the outer end 4 of the enlargement 4 is closed or fused down and the electrode 7 sealed therethrough.

While for the sake of illustration, one em'- bodiment of the invention has been shown and specifically described, it is to be understood that various changes in the construction, shape and arrangement of the parts may be made within the spirit of the invention and the scope of the sub-joined claims and particularly it is contemplated to use an inwardly directed supporting member integral 'with the outer envelope instead of the outwardly directed supporting member 4, the inwardly directed supporting portionl of the outer en velope extending into the upper open end of the protective element instead of therearound and being united thereto by a ring of cement located between its outer periphery and the inner periphery of the protective element. ln other words, the supporting portion of the outer envelope may be displaced laterally either outwardly or inwardly.

rlhe invention claimed is:

l. A. mercury switch comprising an outer envelope having a laterally displaced supporting portion, a protective element having one end yieldably supported thereon, said protective element being of tubular form and having its lower end closed and providing a well and having an intermediate portion partially separated from thermain portion and displaced inwardly to provide an opening between the well and the interior ofthe envelope and to provide a. shield, a body of mercury having a portion in the well and having a shiftable portion making and breaking contact with the portion in the well, an electrode sealed through the outer envelope and projecting into the well behind the shield and an electrode sealed through the outer envelope and immersed in the shiftable portion of the mercury.

2. A mercury switch comprising an hermetically sealed outer envelope, a protective element in the outer envelope having a portion partially separated from the main portion thereof and displaced relative to the main portion toprovide an opening through the protective element and a shield adjacent said opening, a body of mercury having portions making and breaking contact on a surface of the protective element defining the opening therethrough, and an electrode projecting down behind the shield and into theVV lLeashes portion of the mercury located belowl the shield. I

3. A mercury switch. comprising an hermetically sealed outer envelope having its s upper portion formed with an outwardly di- A rected tubular supporting member, a protective element of arc resisting material in the form of a cylinder having its upper end open and its lower end closed, the upper o n end A l.. of the cylinder being fitted in the tub ar supporting member and yieldably suspended therein, the lower end of the protective element being spaced from the outer envelope and defining a well, said protective element having an opening therein permitting' of communication between the interior of the well and the interior of the outer envelope,

4 and a body of mercury having a portion in the well and a portion inthe outer envelope,

v said portions of the mercury making and breakmg contact on a surface of the protective element. y v

'4. A mercury switch comprising an hermetically sealed outer envelope having a main body provided with an outwardly directed enlargement in the upper part thereof, a protective element of arc resistant material having a portion disposed in `said enlargement, yieldable supporting means between said portion of theV rotective -elementand the enlargement, allo said protective element except said portion thereof being spaced from and out4 of contact with said outer envelope, and a body of mercury in the outer envelope having portions uniting and dividing on a surface of the protective element.

5; A mercury switch comprising an hermeticall sealed outer envelope having a laterally dlsplacedportion in its upper part, a 40 protective element having its upper part interftt'ed with and `Suspended onsaid laterally displaced portionofits outer envelope, said protective element having a well in its lower portion spaced from and out of contact with the outer envelo e and also having an opening permitting o communication between the interior of the well and the interior of the outer envelope, and a body of mercury v.having a portion in the outer envelope and a portion in the well, said portions of the mercury making andbreaking contact on a surface of the lower part 'of the protective element.A y

Inwitness whereof, I hereto aix my signature. 

